Level posture sensing chip and its manufacturing method, level posture sensor

ABSTRACT

The present invention discloses a gas pendulum style level posture sensing chip and its manufacturing method and a level posture sensor. The gas pendulum style level posture sensing chip includes: a semiconductor substrate; two sets of arm thermosensitive fuses formed on the surface of the semiconductor substrate, each set of the thermosensitive fuses including two thermosensitive fuses in parallel to each other, the two sets of thermosensitive fuses being vertical to each other; electrodes formed at the two ends of the thermosensitive fuses. For the level posture sensing chip and sensor provided by the present invention, the parallelism and verticality of the thermosensitive fuses is high in precision such that the more accurate measurement can be implemented.

TECHNICAL FIELD

This invention relates to the technical field of level posture measuringof a carrier, and particularly, to a level posture sensing chip and itsmanufacturing method and a micro-machined gas pendulum style levelposture sensor.

BACKGROUND

The conventional level posture sensor contains a solid pendulum styleand a liquid pendulum style. The two pendulum styles level posturesensors both have the disadvantages of a complex structure, a badanti-impact performance and long responding time and so on to a variousdegree. A one dimension gas pendulum style level posture sensor using“gas pendulum” instead of “solid pendulum” or “liquid pendulum” isprovided in the invention whose application number is 93216480.3 filedby the present applicant with the Chinese Patent Office. This levelposture sensing element generally utilizes a single-chamber double-fusesstructure where there are two thermosensitive fuses in the hermeticchamber through which constant currents flow. The thermosensitive fusesheat the gas in the chamber as a heat source, and at the same time thethermosensitive fuses are also used as measuring elements, the twothermosensitive fuses composing two arms of a signal detecting bridge.When the one dimension gas pendulum style level posture sensing elementis in a horizontal state, the hot airflows generated by the twothermosensitive fuses are both in vertical upward directions, both ofthem are on an identical isotherm, the resistances of the twothermosensitive fuses are the same, the bridge is in balance, and theoutput voltage of detecting circuit is 0. When the sensing chamber isinclined an angle degree relatively to horizontal surface, the twothermosensitive fuses are on different isotherms separately, theresistances of the thermosensitive elements vary differently, theresistances of the two thermosensitive fuses are unequal, the bridge isout of balance, and a voltage proportional to the inclination angle isoutput.

However, the one dimension structure level posture sensing element canonly sense level posture in one direction. If a two dimension levelposture needs to be measured, two sensors amounted vertically must beused such that the volume is much lager than that of the one dimension;meanwhile the cross coupling of the axes is often larger because of thegreater difficulty of the vertical amounting. Moreover, thethermosensitive fuses function both as detecting temperature and asheating at the same time. To ensure that the thermosensitive fuses couldhave sensitivity high enough and chamber temperature, the currentflowing in the thermosensitive fuses is generally large, the temperatureof the thermosensitive fuses is high, and the detecting performance ofthe thermosensitive fuses is reduced such that the stability of thesensor becomes poor.

For the purpose of improving performance and reducing cost anddecreasing volume, 13^(th) Institute of CETC issues “Research onreliability of the MEMS convective accelerometer” (MicronanoelectronicTechnology, 2003, July-August, pages 317-320) wherein a resistance of afuse is between 3000-10000.

The processes used in “Micromachined Convective Accelerometer” reportedby Hebei Semiconductor Research Institute (Chinese Journal ofSemiconductors, 2001, Vol. 22, No. 4, pages 465-468) are those:thermally growing a layer of SiO₂ on (100) Si, depositing a layer ofpolysilicon, then photo etching, and boron diffusing the polysilicon toinform resistor strips, and finally depositing a layer of siliconnitride (SiN_(x)) so as to construct a polysilicon thermosensitiveresistor and a heat resistor.

SUMMARY OF THE INVENTION

In view of above, the present invention solves a technical problem toprovide a gas pendulum style level posture sensing chip with highmeasurement accuracy.

The gas pendulum style level posture sensing chip provided by thepresent invention includes: a semiconductor substrate; two sets of armthermosensitive fuses formed on the surface of the semiconductorsubstrate, each set of the thermosensitive fuses including twothermosensitive fuses in parallel to each other, the two sets ofthermosensitive fuses being vertical to each other; electrodes formed atthe two ends of the thermosensitive fuses.

Further, the level posture sensing chip of the present invention alsoincludes: an arm heating fuse formed on the surface of saidsemiconductor substrate, said heating fuse being disposed along thesymmetrical position of the same set of thermosensitive fuses;electrodes formed at the two ends of said heating fuse.

According to an embodiment of the present invention, the two sets ofthermosensitive fuses constructs a rectangular and shares a heating fusedisposed on a diagonal of the rectangular.

According to an embodiment of the present invention, each set of thethermosensitive fuses has a heating fuse disposed along the middleposition of the same set of the two thermosensitive fuses.

According to an embodiment of the present invention, the semiconductorsubstrate is a silicon substrate, said thermosensitive fuses and saidheating fuse are both mostly composed of Pt. The widths of thethermosensitive fuses and the heating fuse are 40-60 μm, the lengthsthereof are 1200-1600 μm, and the spaces between fuses are 500-1000 μm.

Another problem solved by the present invention is to provide amicromachined gas pendulum style level posture sensor.

The micromachined gas pendulum style level posture sensor provided bythe present invention includes: a casing, a base, an angular velocitygyroscope, a signal processing circuit, a sensing element including thelevel posture sensing chip described above. The sensing chip and theangular velocity gyroscope are amounted on the base. The sensing chipoutputs a tilt signal to said signal processing circuit, the angularvelocity gyroscope outputs an angular velocity signal to said signalprocessing circuit, said signal processing circuit processes said tiltsignal and said angular velocity signal to output a level posturevoltage signal.

Another technical problem solved by the present invention is to providea semiconductor chip manufacturing method.

The semiconductor chip manufacturing method provided by the presentinvention includes the steps of: forming a mask layer on a surface of asemiconductor substrate; forming thermosensitive fuses and a heatingfuse on said mask layer; forming electrodes at the ends of saidthermosensitive fuses and said heating fuse; and forming an arm byetching the area of the semiconductor substrate where saidthermosensitive fuses and said heating fuse are by combining dry methodwith wet method.

Further, the step of forming the thermosensitive fuses and the heatingfuse on the mask layer described above includes: forming a first patternon said mask layer by photo etching; and forming the thermosensitivefuses and the heating fuse composed of metal or alloy on said firstpattern by sputtering or evaporating.

The step of forming electrodes at the ends of said thermosensitive fusesand said heating fuse includes: forming a second pattern on said surfaceof the semiconductor by photo etching; and forming the electrodes onsaid second pattern by evaporating, said electrodes being disposed atthe ends of said thermosensitive fuses and said heating fuse.

The step of forming the arm includes: forming a third pattern aroundsaid thermosensitive fuses and said heating fuse on the surface of saidsemiconductor by photo etching; forming thermosensitive fuse cylindersand a heating fuse cylinder by dry method etching; and forming armthermosensitive fuses and an arm heating fuse by wet method etching.

Furthermore, it also includes the step of: heat-processing saidsemiconductor chip under the temperature of 300-800° C.

According to the gas pendulum style level posture sensing chip providedby the present invention, by the micromachined processing techniquemanufacturing, the degree of parallelization and verticality of thethermosensitive fuses is high in precision so as to implement the higheraccuracy of measurement.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic illustrative diagram of operating principle of amicromachined gas pendulum style level posture sensor;

FIG. 2 is a structural illustrative diagram of an embodiment of a gaspendulum style level posture sensing chip according to the presentinvention;

FIG. 3 is a structural illustrative diagram of another embodiment of thelevel posture sensing chip according to the present invention;

FIG. 4 is a structural illustrative diagram of another embodiment of thelevel posture sensing chip according to the present invention;

FIG. 5 a is an illustrative diagram of a level posture sensing elementin a rectangular structure;

FIG. 5 b is an illustrative diagram of a level posture sensing elementin a semicircular structure;

FIG. 6 is a flowchart of an embodiment of a manufacturing method of thegas pendulum style level posture sensing chip according to the presentinvention;

FIG. 7 is a flowchart of another embodiment of the manufacturing methodof the level posture sensing chip according to the present invention;

FIG. 8 a is an illustrative diagram of a mask board used for first photoetching;

FIG. 8 b is an illustrative diagram of a mask board used for secondphoto etching;

FIG. 8 c is an illustrative diagram of a mask board used for third photoetching;

FIG. 9 is a sectional view of part positions of the chip during the chiparm manufacturing of the micromachined gas pendulum style level posturesensor;

FIG. 10 is a flowchart of package testing for the micromachined gaspendulum style level posture sensing element;

FIG. 11 is a structural illustrative diagram of a signal obtainingcircuit of the micromachined gas pendulum style level posture sensor;

FIG. 12 is a structural illustrative diagram of the micromachined gaspendulum style level posture sensor;

FIG. 13 is a schematic diagram of a signal processing circuit of themicromachined gas pendulum style level posture sensor.

DETAILED DESCRIPTION OF EMBODIMENTS

The present invention will be described in more details with referenceto the drawings below, wherein illustrative embodiments of the presentinvention are explained.

FIG. 1 is a schematic illustrative diagram of operation principle of amicromachined gas pendulum style level posture sensor. Its principle isto utilize the pendulum characteristic of natural convection gas in ahermetic chamber in which two thermosensitive fuses in parallel aredisposed as two arms of a bridge. In FIG. 1, 10 indicates a heat source,11 indicates a normal line of the plane where the thermosensitive fusesare, 12 indicates the direction of gasflow. As shown in FIG. 1 a, whenthe sensor is placed horizontally, the hot gasflow is vertical upward tothe plane where the thermosensitive fuses are, where the quantities ofheat absorbed by the two thermosensitive fuses are equal, thetemperatures are equal, and the bridge achieves balance. As shown inFIG. 1 b, when the sensor tilts an angle θ, the hot gasflow remains tokeep vertical upward because of the characteristic of pendulum, butdeparts a tilt θ from the normal line of the plane where thethermosensitive fuses are such that the quantities of heat absorbed bythe thermosensitive fuses are different, the temperatures are alsodifferent with the result that the bridge is out of balance, and avoltage signal proportional to the tilt is output:

V₀=Kθ  (1)

K in the equation above is a scale coefficient (mv/°). When the tiltsensing direction is opposite, the symbol of the output voltage is alsoopposite.

FIG. 2 is a structural illustrative diagram of an embodiment of a gaspendulum style level posture sensing chip according to the presentinvention. As shown in FIG. 2, the level posture sensing chip includes asilicon wafer 20 as a substrate, two set of thermosensitive fuses 21 andheating fuse 22 in parallel to each other formed on the silicon wafer20, electrodes 23 formed at the ends of the thermosensitive fuses andthe heating fuse and chambers 24 and 25 formed under each set of thethermosensitive fuses. Arrows 26 and 27 indicate a sensing axis(parallel to the direction of the thermosensitive fuse) of each set ofthe thermosensitive fuses separately, and tilting a certain positive andnegative angle can be done around the axis. The tilt in two directionsvertical to each other can be measured by the structure shown in FIG. 2.The thermosensitive fuses and the heating fuse can be mostly composed ofplatinum (Pt), and thermosensitive resistance material or alloy such asplatinum-lawrencium, nickel-chromium-aluminum etc. can be used as well.

According to an embodiment of the present invention, widths of thethermosensitive fuses and the heating fuse are 40-60 μm, lengths thereofare 1200-1600 μm, and spaces between fuses are 500-1000 μm.

FIG. 3 is a structural illustrative diagram of another embodiment of thelevel posture sensing chip according to the present invention. In thisembodiment, two sets of thermosensitive fuses shares a heating fuse. Asshown in FIG. 3, L and W separately indicate the length direction andthe width direction of the chip, i.e. X axis and Y axis directions. Thelevel posture sensing chip in the figure includes a substrate 30, anelectrode 31 formed on the substrate, a heating fuse 32, thermosensitivefuses 33 and 34 along the width direction of the chip andthermosensitive fuses 35 and 36 along the length direction of the chip.The same set of the thermosensitive fuses are disposed in parallel, andthe different set of the thermosensitive fuses are vertical to eachother. The two sets of the thermosensitive fuses shares the identicalheating fuse 32, and the heating fuse is along the symmetrical positionof the thermosensitive fuses. For example, four thermosensitive fusesform a rectangular (for example, a square), and the heating fuse is atthe position of the diagonal of the rectangular. The thermosensitivefuses and the heating fuse are formed in arm structures by manufacturingprocesses, and a chamber under the thermosensitive fuses and the heatingfuse is formed in the substrate. The electrode 31 on the substrate canbe mostly composed of metal such as gold, silver, copper, aluminum, andetc., and also can be composed of alloy. Besides using silicon, thesubstrate also can use germanium, selenium, and etc.

FIG. 4 is a structural illustrative diagram of another embodiment of thelevel posture sensing chip according to the present invention. As shownin FIG. 4, L and W separately indicate the length direction and thewidth direction of the chip. The level posture sensing chip in thefigure includes a substrate 40, an electrode 41 formed on the substrate,thermosensitive fuses 43 and 44 and a heating fuse 42 along the widthdirection of the chip and thermosensitive fuses 46 and 47 and a heatingfuse 45 along the length direction of the chip. The same set of thethermosensitive fuses and the heating fuse are in parallel to eachother, and the different set of the thermosensitive fuses and theheating fuse are vertical to each other. The heating fuse 42 is disposedalong the middle position of the thermosensitive fuses 43 and 44, andthe heating fuse 45 is disposed along the middle position of thethermosensitive fuses 46 and 47. The thermosensitive fuses and theheating fuse are formed in arm structures by manufacturing processes,and a chamber is formed on the area of substrate where thethermosensitive fuses and the heating fuse are.

Using the heating fuse, output signal can be increased and the stabletime can be shortened. If the heating fuse is not used, the signaloutput of each set of the thermosensitive fuses is small. At the sametilt, the sensitivity level of the output signals in the presence of theheating fuse is increased by 6-8 times than that without the presence ofthe heating fuse. For the sensor chips in the same space, the stabletimes of the output voltages are different in the presence of or withoutthe presence of the heating fuse, and the heating fuse can enable thestable time of the output voltage to be shortened.

The thermosensitive fuse resistor R1 and the heating fuse resistor R2can be expressed as followed:

$\begin{matrix}{{R\; 1} = {\rho \; \frac{L_{1}}{S_{1}}}} & (2) \\{{R\; 2} = {\rho \; \frac{L_{2}}{S_{2}}}} & (3)\end{matrix}$

wherein ρ is the resistivity of Pt; L₁ and L₂ are the lengths of thethermosensitive fuses and the heating fuse separately; S₁ and S₂ are thecross sectional areas of the thermosensitive fuses and the heating fuseseparately. In case that the cross sections of the thermosensitive fusesand the heating fuse are rectangular, S=W×H, that is, the crosssectional area is equal to the product of the length and the width. Tocompute the required resistance by equation (2) and equation (3), notonly the possibility of the micromachining manufacturing and themechanistic characteristic of the fuse must be considered, but alsoacquiring the required output signal must be also considered. Therefore,the optimal sizes of the thermosensitive fuses and the heating fuse mustbe determined by experiment.

The thermosensitive fuses and the heating fuse of Pt are a littleslender, and they can be aged for a long time at the voltage higher thanan operating voltage to increase its operation stability. Beforepower-on operation, the chip is heat-processed for 2 h (2 hours) under300-800° C. to improve the crystal grain arrays of the thermosensitivefuses and the heating fuse so as to increase the operation stability ofthe chip thereof. Table 1 below shows the experiment result of the twosets of fuses power-on working for 40 h:

TABLE 1 Power-on Voltage of A set (V) Voltage of B set (V) workingheating thermosensitive thermosensitive heating thermosensitivethermosensitive time (h) fuse fuse 1 fuse 2 fuse fuse 1 fuse 2 0 1.6381.489 2.789 1.339 1.314 2.514 15 1.585 1.490 2.786 1.340 1.316 2.511 201.576 1.482 2.778 1.330 1.308 2.501 24 1.573 1.479 2.777 1.330 1.3162.509 40 1.581 1.488 2.791 1.326 1.308 2.501

Seeing from Table 1, after the continuous power-on working for 40 h, thevoltage variation in the fuses is <±0.3%, which indicates that theresistance variation is vary small and the stability of the sensor isquite well on condition that the thermosensitive fuses and the heatingfuse are at the same work temperature.

In case that chips with a single heating fuse and chips with doubleheating fuses are respectively placed in an identical casing, and in thesame condition, the sensitivity level of the output signal of the chipwith the single heating fuse is smaller by about 20-30% than that of thechip with two heating fuses.

The level posture sensing chip can be amounted in different chambers.FIG. 5 is an embodiment of the chamber, wherein there is a chamber in arectangular structure in FIG. 5 a, with the inner space size of 2 cm×1.8cm×0.4 cm, and the volume of 1.44 cm³. In FIG. 5 b, there is a chamberin a semicircular structure, with the diameter of the chamber of 0.7 cm,the height of 0.5 cm, and the volume of 0.77 cm³.

Table 2 below shows the experiment result of output signals (tilt ±80°)of different chamber structures in the case that the first levelamplifying same-kind detecting circuit is used and the heating fuse areat different bias voltages:

TABLE 2 rectangular structure semicircular structure bias voltage (V)voltage (mV) voltage (mV) 2.35 ±110 ±100 1.83 ±90 ±80 1.45 ±60 ±55 1.15±35 ±35 0.76 ±20 ±20 0.56 ±15 ±15

Seeing from the data in Table 2, chamber structures with differentshapes and different volumes have little effect on the output signals.

FIG. 6 is a flowchart of an embodiment of a manufacturing method of thegas pendulum style level posture sensing chip according to the presentinvention.

As shown in FIG. 6, at step 601, a mask layer is formed on asemiconductor substrate. For example, when the substrate is a (100)silicon wafer, SiO₂ is grown on the surface of the silicon wafer suchthat a mask can be formed on the surface of the silicon wafer to protectthe surface of the silicon wafer and to provide processing conditionsfor the following processes.

At step 603, thermosensitive fuses and a heating fuse are formed on themask layer. Using the pattern formed on the mask layer by photo etching,the thermosensitive fuses and the heating fuse are formed by depositingmetal (e.g. platinum, etc) or alloy (platinum lawrencium, nickelchromium aluminum, etc) on the mask layer using a sputtering orvaporization process.

At step 605, electrodes are formed at the ends of the thermosensitivefuses and the heating fuse. Using the electrode pattern formed on thesurface of the chip by photo etching, and the electrode is formed bysputtering. The sputtering material can be metal, such as gold, silver,copper, aluminum etc, or alloy. The electrode also can be formed by theway of vaporization.

At step 607, thermosensitive fuse cylinders and a heating fuse cylinderare formed by dry method etching.

At step 609, arm structures are formed at the areas of the substrateunder the thermosensitive fuses and the heating fuse by wet methodetching. After processing of this step, chamber bodies are formed at theareas under the thermosensitive fuses and the heating fuse, and thethermosensitive fuses and the heating fuse form the arm structures.

FIG. 7 is a flowchart of another embodiment of the manufacturing methodof the level posture sensing chip according to the present invention.

As shown in FIG. 7, at step 701, a silicon dioxide layer is formed onthe selected surface of the silicon wafer by oxidation and the siliconwafer can be cleaned before forming the silicon dioxide layer. The crosssections of the oxidized surface of the silicon wafer at (A-A) and (B-B)are shown in FIG. 9( a).

At steps 703 and 705, the surface of the silicon wafer is subject to thefirst photo etch by using a first mask board shown in FIG. 8 a, and atstep 705, plating Ti and Pt is finished. The cross sections at (A-A) and(B-B) are formed, as shown in FIG. 9( b). Plating Ti serves to be a baseand to enhance the combination of Pt and SiO₂.

At steps 707 and 709, the surface of the silicon wafer is subject to thesecond photo etch by using a second mask board shown in FIG. 8 b, andelectrodes composed of Ti and Au and corresponding to thethermosensitive fuses and the heating fuse are formed on the pattern ofthe surface of the silicon wafer by sputtering. The material forsputtering also can be other metal such as copper, aluminum, silver, orother alloy material. After plating Ti and Au, the cross sections of thesurface of the silicon wafer at (A-A) and (B-B) are shown in FIG. 9( c).

At step 711, the surface of the silicon wafer is subject to the thirdphoto etch by using a third mask board, and a corresponding pattern isformed on the surface of the silicon wafer. The mask board used is shownin FIG. 8 c.

At step 713, the dry method depth etching is made. The etching depth canbe 100-140 μm. The situations of the corresponding surface of thesilicon wafer after the dry method depth etching are shown in FIG. 9(d). Making the depth etching establishes a foundation for later armprocessing.

At step 715, an arm structure is formed by wet method etching. Theobtained corresponding arm situations are shown in the (A-A) crosssections of FIG. 9( d).

Proper feeding speed, dicing width and water flow speed are selected,and the silicon wafer is cut into small chips. The semiconductor chipmay be sliced according to conditions after forming arm structures. Andit is also possible to slice the semiconductor chip before step 715 inorder to improve the rate of finished products.

FIG. 10 is a flowchart of encapsulation testing for the level posturesensing chip after finishing slicing.

As shown in FIG. 10, at step 1101, chip for which slicing is finished issorted.

At step 1103, adhesive is selected, and the chip is adhered to thecasing.

At step 1105, electrodes and wires are connected, and soldering andassembling are made.

At step 1107, the packaged chip is connected to a back end circuit, andthe assembled circuit is debugged.

At step 1109, the packaged sensing element is tested in performance byusing instrument equipments.

FIG. 11 is a circuit diagram of a signal obtaining circuit of the levelposture sensor according to the present invention. As shown in FIG. 11,the signal obtaining circuit includes a tilt sensor 121, a first levelamplifier 122, a second level amplifier 123 and a compensating circuit124. In FIG. 1, the tilt sensor 121 includes a resistor 1210 composed ofthermosensitive fuses and a resistor 1211 composed of a heating fuse.The resistor 1210 composed of thermosensitive fuses and two outerreference resistors R constructs a bridge, and when the sensor tiltsrespective to the level plane, two thermosensitive fuses in the bridgesense different temperatures with the result that the bridge is out ofbalance, outputting a voltage signal corresponding to the level posturetilt. The first level amplifier 122 and the second level amplifier 123includes operational amplifiers 1221 and 1231 respectively, andamplifies the voltage signal output by the tilt sensor 121 to adjust toa defined V₀ for compensation. The final output is the voltage V_(out)representing the tilt θ.

FIG. 12 is a structural illustrative diagram of an embodiment themicromachined gas pendulum style level posture sensor according to thepresent invention. As shown in FIG. 12, the sensor includes a base 131,a level posture sensing element 132, an angular velocity gyroscope 133,a signal processing circuit 134, a casing 135 and a socket 136. In FIG.12, the level posture sensing element 132 is configured by packaging thelevel posture sensing chip of the present invention. The level posturesensing element 132 is used to output a tilt voltage to the signalprocessing circuit 134. The angular velocity gyroscope 133 is used tooutput an angular velocity voltage to the signal processing circuit 134.The signal processing circuit 134 processes the received tilt voltageand the angular velocity voltage, and can obtain two dimension andomniberaing level posture output voltages after signal processing andoutput an interference-eliminated tilt voltage and an angular velocityvoltage. Thus, the micromachined level posture sensor and themicromachined angular velocity gyroscope are combined to eliminate theinterference of the moving base by the gyroscope so as to obtain thelevel posture output after eliminating the interference of the movingbase.

FIG. 13 is a schematic diagram of the principle a signal processingcircuit of the micromachined gas pendulum style level posture sensoraccording to the present invention. As shown in FIG. 13, the circuitincludes a two dimension level posture sensing element 141, an angularvelocity gyroscope 142, a bridge circuit 143, an amplifying circuit 144,a temperature sensor 145, a singlechip 146 and an amplifying circuit147. The angular velocity gyroscope 142 detects the angular velocity ωand sends it to the bridge circuit 143, the two dimension level posturesensing element 141 detects a tilt θ and an interference angle θ′ andsends them to the bridge circuit 143, the bridge circuit 143 convertsthe received signals to electrical signals and sends them to theamplifying circuit 144 for amplifying and forwarding to the singlechipfor process. The temperature sensor 145 sends the detected temperaturesignal to the singlechip for processing. The singlechip processes thereceived signals and then sends them to the amplifying circuit 147, andan angular velocity voltage signal Vω and a tilt voltage signal V_(θ)are output by the amplifying circuit. The singlechip includes a zero andsensitivity compensating module 1461, a linearity and output module1462, a posture interference eliminating module 1463 and an omniberainglevel posture signal compensating module 1464.

For the level posture sensor, it can be referenced to the relateddescription in Chinese Patent Publication No. CN101071066A. The maintechnical criteria of the micromachined gas pendulum style level posturesensor of the present invention is shown in Table 3 below:

TABLE 3 Inhibiting Measurement Respond interference range timeResolution Nonlinearity efficiency ±45° ≦80 ms ≦0.01° ≦1% ≧95%

In the micromachined gas pendulum style level posture sensor provided bythe present invention, the chip of the level posture sensor ismanufactured by micromachined silicon processing technology, and theparallelism and verticality of the thermosensitive fuse is high inprecision. The silicon processing technology for the micromachined gaspendulum style level posture sensor such as photo etching, depthetching, sputtering, etching and so on can accurately control theresistance of the thermosensitive fuse and manufacture chips with goodperformance uniformity. The chip size of the micromachined gas pendulumstyle level posture sensor can be small to be below 4×4 mm², and on a 4inches chip, more than 100 chips can be manufactured with the result ofthe easy implementation of mass production.

The description of the present invention is provided for the purpose ofillustration and description, rather than being exhaustive or limitingthe present invention to the disclosed form. Many modifications andvarieties are obvious to those ordinarily skilled in the art.Embodiments are selected and described to explain the theory andpractical application of the present invention better, and to enablethose ordinarily skilled in the art to understand the present inventionso as to design various embodiments with various modificationsappropriate for specific uses.

1. A gas pendulum style level posture sensing chip, comprising: asemiconductor substrate; two sets of arm thermosensitive fuses formed onthe surface of the semiconductor substrate, each set of thethermosensitive fuses including two thermosensitive fuses in parallel toeach other, the two sets of thermosensitive fuses being vertical to eachother; and electrodes formed at the two ends of the thermosensitivefuses.
 2. The level posture sensing chip of claim 1, further comprising:an arm heating fuse formed on the surface of the semiconductorsubstrate, the heating fuse being disposed along the symmetricalposition of the same set of thermosensitive fuses; and electrodes formedat the two ends of the heating fuse.
 3. The level posture sensing chipof claim 2, wherein the two sets of thermosensitive fuses constructs arectangular and shares a heating fuse disposed on a diagonal of therectangular.
 4. The level posture sensing chip of claim 2, wherein eachset of the thermosensitive fuses has a heating fuse disposed along themiddle position of the same set of two thermosensitive fuses.
 5. Thelevel posture sensing chip of claim 2, wherein the thermosensitive fusesand/or heating fuse are both mostly composed of Pt.
 6. The level posturesensing chip of any one of claim 2, wherein the widths of thethermosensitive fuses and the heating fuse are 40-60 μm, the lengthsthereof are 1200-1600 μm, and the spaces between fuses are 500-1000 μm.7. The level posture sensing chip of claim 2, wherein the electrodes arecomposed of gold, silver, copper or aluminum.
 8. The level posturesensing chip of claim 1, wherein the electrodes are composed of gold,silver, copper or aluminum.
 9. The level posture sensing chip of claim1, wherein the semiconductor substrate is a silicon substrate or agermanium substrate.
 10. A micromachined gas pendulum style levelposture sensor, comprising a casing, a base, an angular velocitygyroscope, a signal processing circuit, a sensing element including thelevel posture sensing chip of claim 1, the sensing chip outputting atilt signal to the signal processing circuit, the angular velocitygyroscope outputting an angular velocity signal to the signal processingcircuit, the signal processing circuit processing the tilt signal andthe angular velocity signal to output a level posture voltage signal.11. The level posture sensing chip of claim 10, further comprising: anarm heating fuse formed on the surface of the semiconductor substrate,the heating fuse being disposed along the symmetrical position of thesame set of thermosensitive fuses; and electrodes formed at the two endsof the heating fuse.
 12. The level posture sensing chip of claim 10,wherein the two sets of thermosensitive fuses constructs a rectangularand shares a heating fuse disposed on a diagonal of the rectangular. 13.The level posture sensing chip of claim 10, wherein each set of thethermosensitive fuses has a heating fuse disposed along the middleposition of the same set of two thermosensitive fuses.
 14. The levelposture sensor of claim 10, wherein the signal processing circuit alsooutputs an angular velocity voltage.
 15. A semiconductor chipmanufacturing method, comprising the steps of: forming a mask layer on asurface of a semiconductor substrate; forming thermosensitive fuses anda heating fuse on the mask layer; forming electrodes at the ends of thethermosensitive fuses and the heating fuse; and forming an arm byetching the area of the semiconductor substrate where thethermosensitive fuses and the heating fuse are.
 16. The semiconductorchip manufacturing method of claim 15, wherein the semiconductorsubstrate is a silicon wafer, and the mask layer is silicon dioxide orsilicon nitride.
 17. The semiconductor chip manufacturing method ofclaim 15, wherein the step of forming the thermosensitive fuses and theheating fuse on the mask layer including: forming a first pattern on themask layer by photo etching; and forming the thermosensitive fuses andthe heating fuse composed of metal or alloy on the first pattern bysputtering or evaporating.
 18. The semiconductor chip manufacturingmethod of claim 17, wherein the alloy is platinum lawrencium or nickelchromium aluminum.
 19. The semiconductor chip manufacturing method ofclaim 15, wherein the step of forming electrodes at the ends of thethermosensitive fuses and the heating fuse includes: forming a secondpattern on the surface of the semiconductor by photo etching; andforming the electrodes on the second pattern by evaporating, saidelectrodes being disposed at the ends of the thermosensitive fuses andthe heating fuse.
 20. The semiconductor chip manufacturing method ofclaim 15, wherein the step of forming the arm includes: forming a thirdpattern around the thermosensitive fuses and the heating fuse on thesurface of the semiconductor by photo etching; forming thermosensitivefuse cylinders and heating fuse cylinder by dry method etching; andforming arm thermosensitive fuses and an arm heating fuse by wet methodetching.
 21. The semiconductor chip manufacturing method of claim 15,further comprising the step of heat-processing the semiconductor chipunder the temperature of 300-800° C.